Core C will provide the personnel and expertise to conduct all the PET imaging studies and will provide the software tools and statistical support needed by the projects for data analysis. We have combined the previous data analysis core and imaging core together because of the considerable overlap of responsibilities (i.e., it is not entirely clear when image reconstruction ends and data processing begins), and because many of the data analysis tools have now been developed, with the major task now being one of practical implementation. The imaging support will include scheduling studies. patient education, patient positioning, placement of vascular catheters, injection of radiopharmaceuticals, blood sampling, assistance in gamma counting of samples and in use of the blood gas and glucose analyzers, tomographic data acquisition, image reconstruction and archiving, and all the appropriate quality control checks of the tomograph and ancillary equipment. The data analysis support will include: 1) automated preparation of blood counts and tissue region-of-interest data; 2) a general purpose program (Viewbox) for image display and manipulation; 3) a set of parameter optimization programs to model whole body blood time-activity curves; 4) a set of parameter optimization programs to model tissue uptake of each relevant radiopharmaceutical; 5) construction of metabolic images using the technique of mixture analysis; 6) optimization of simple imaging protocols to make the protocols more widely applicable; and 7) biostatistical support to help design studies, test hypotheses, and compare visual interpretation with quantitative imaging. This support is essential for the projects to ensure that the studies are done in an effective manner with valid, quantitative data analysis.